PROJECT SUMMARY/ABSTRACT In this proposal for a K01 Mentored Research Scientist Development award, Shashi Kapadia, MD MS proposes a training and research program that will enable him to become an independent physician-researcher focused on policy and systems factors that impact drug user health. Dr. Kapadia is currently an Instructor in Medicine in the Division of Infectious Diseases at Weill Cornell Medicine whose research focuses on hepatitis C (HCV) treatment access for people who inject drugs (PWID). To achieve his long-term goal, Dr. Kapadia will obtain skills in evaluating care delivery models that integrate medical and behavioral health care, particularly the care of substance use disorders. He will learn methodological approaches to policy research that include natural experimental designs and analysis of administrative/claims data, conducting mixed-methods research, and using simulation models to predict the impact of public health interventions. He will achieve these training objectives with a combination of formal coursework, rotations in diverse care settings, mentorship, and hands-on research experience. He will be mentored by Dr. Bruce Schackman (primary), Dr. Yuhua Bao, Dr. David Perlman, Dr. Kristen Marks, and Dr. Erika Martin, as well as a team of expert consultants. Combined, these individuals have expertise in all of the training areas that Dr. Kapadia seeks to develop during this award period. The population health problem that Dr. Kapadia will study during the proposed career development award is the need to improve access to HCV treatment for PWID, with a focus on New York State. Expanded treatment access is needed to prevent long-term morbidity and mortality from liver disease, and can potentially eliminate HCV transmission. Integrating HCV treatment into primary care and substance use treatment settings may help alleviate barriers to expanded treatment. In his proposed research, Dr. Kapadia will use data from New York State Medicaid to study trends in HCV treatment uptake in primary care (Aim 1). He will conduct interviews to contextualize these quantitative findings, and to elicit factors that would further support treatment integration into primary care, substance use treatment, and syringe service programs. (Aim 2). He will then develop a simulation model, based on these findings, to forecast the impact of integrated care models on HCV treatment of PWID in New York State (Aim 3). The proposed research will test whether integrated HCV care is being effectively utilized, describe the barriers to achieving it, and analyze its impact on the health of HCV-infected individuals, especially PWID. It will be relevant to policymakers and public health practitioners. Additionally, the skills that Dr. Kapadia will gain through completion of this mentored research and training plan will enable him to seek future R01 funding and achieve his goal of becoming an independent investigator.